It is known that such valves, and more particularly those designed to be subjected to difficult operating conditions, e.g. valves for cryogenic fluids, need to present both static sealing relative to the outline of their bodies, and dynamic sealing between the shutter member and a peripheral thrust ring. Unfortunately, although satisfactory static sealing is provided by compressing an O-ring between the thrust ring and a portion of the valve body having a compression-limiting rim, completely satisfactory dynamic sealing is not obtained since the dynamic sealing ring that is designed to be subjected to the pressure of the shutter member does not remain centered relative to the shutter member while it is being closed, and this gives rise to variations in the specific contact pressure between the shutter member and the dynamic sealing ring, and consequently gives rise to the possibility of leaks at certain points around the periphery thereof. In addition, it is difficult to obtain sealing rings that present sufficient elastic resistance to crushing by the shutter member (referred to below as "restitution").
An object of the present invention is to provide a valve having a metal seal whose specific contact pressure between the thrust ring and the shutter member does indeed remain constant over its entire periphery, and whose dynamic seal provides greater elastic restitution.